1. Field of the Invention
The present invention relates to a coaxial cable, and in particular to coaxial cable useful as thin coaxial cable for high-frequency use that can be used in a twisting and bending portion of mobile communication equipment.
2. Description of the Related Art
As an example of coaxial cable of the prior art, Japanese U.M. Laid-open No. 2280/76 is known. In this coaxial cable, an insulating layer, an outer conducting layer and a protective film layer are formed in that order around a center conductor, the outer conducting layer being formed from a primary transverse winding and a secondary transverse winding of a plurality of thin metal wires, the winding directions of the primary transverse winding and the secondary transverse winding being in opposite directions. While not disclosed in Japanese U.M. Laid-open No. 2280/76, the winding angle has conventionally been from 10.degree. to 20.degree. with respect to the center conductor out of consideration of productivity.
The above-described coaxial cable of the prior art has good high-frequency transmission characteristics, but is subject to frequent wire breakage when used in the twisting and bending portion of a portable telephone or other equipment.